Changelog

• fixes a bug where the "save as" command does not append the .wallet extension
• fixes a bug where the user could still save the wallet in the install directory by placing it in a subfolder, causing the wallet file to be wiped on wallet upgrade
• electron-builder updated for MacOS Catalina compatibility
• updates GH builds to use latest OS and cache the dependencies
• upgrades the wallet backend to alleviate a bug that was (possibly) effecting sending transactions
• Slight configuration change in an attempt to make the sync process not effect the GUI responsiveness so much